Containers for storing food are well known in the art. It is well known that such containers may be produced from many different materials and combinations of materials, e.g., paperboard, glass, aluminum and certain plastics. There are, of course, advantages and disadvantages which inhere in the use of each of those different materials. For example, paperboard is a relatively strong container material but suffers from the disadvantage that it is relatively permeable to gases and, therefore, foods stored in containers constructed solely from paperboard lose their freshness at a relatively rapid rate. On the other hand, glass, aluminum and some plastic materials are relatively impermeable to gases, but to obtain sturdy containers from those materials is expensive because of the relatively high cost of those materials.
It is therefore most desirable in the food container art to provide a container which is sturdy, relatively impermeable to gases and relatively inexpensive. Containers which satisfy each of those three criteria are disclosed in co-pending U.S. application Ser. No. 745,834, filed Nov. 29, 1974, now U.S. Pat. No. 4,155,697, issued May 22, 1979, ('834 application), which disclosure is incorporated herein by reference.
The containers disclosed in the application Ser. No. 745,834 are characterized by horizontal flanges which extend outwardly at least about 1/8 inch from a plastic inner container and vertical flanges which extend at least about 1/8 inch from the horizontal flanges. The plastic inner container is drawn and blow formed into a paperboard outer container. After food is placed into the container disclosed in the application Ser. No. 745,834, the container is sealed with a heat sealable cover, and preferably thereafter, an overcap is provided which engagedly fits around the container at its top.
While the containers disclosed in the application Ser. No. 745,834 are desirably used as containers for food in many instances, in other instances it would be desirable to store food in containers which have screw caps. At the same time it would be desirable that such containers retain the advantages of the containers disclosed in the application Ser. No. 745,834, e.g. sturdiness, relative impermeability to gases and relative inexpensiveness.
The containers of the present invention satisfy the above criteria. The present invention is also directed to a process and apparatus for making such containers.